(LifeScript Health News) The smarter the man, the better the sperm, says a study published in the journal Intelligence.

Researchers at King’s College London, the University of Delaware and the University of New Mexico compared sperm samples with results from intelligence tests given to 425 Vietnam War vets in 1985 as part of the U.S. Centers for Disease Control and Prevention’s Vietnam Experience Study.

The higher the men scored on the exams the more sperm they produced and the better the sperm swam, regardless of smoking and drinking habits and obesity, the study revealed. It concluded that intelligence might be passed down as part of a larger set of positive attributes that also includes sperm quality.